Update to make sure all linked record updates occur in sync with the API call.

packages/server/src/api/controllers/model.js

@@ -1,5 +1,6 @@
 const CouchDB = require("../../db")
 const newid = require("../../db/newid")
+const { EventType, updateLinksForModel } = require("../../db/linkedRecords")
 
 exports.fetch = async function(ctx) {
   const db = new CouchDB(ctx.user.instanceId)
@@ -53,21 +54,6 @@ exports.save = async function(ctx) {
   const result = await db.post(modelToSave)
   modelToSave._rev = result.rev
 
-  const { schema } = ctx.request.body
-  for (let key of Object.keys(schema)) {
-    // model has a linked record
-    if (schema[key].type === "link") {
-      // create the link field in the other model
-      const linkedModel = await db.get(schema[key].modelId)
-      linkedModel.schema[modelToSave.name] = {
-        name: modelToSave.name,
-        type: "link",
-        modelId: modelToSave._id,
-      }
-      await db.put(linkedModel)
-    }
-  }
-
   const designDoc = await db.get("_design/database")
   designDoc.views = {
     ...designDoc.views,
@@ -80,6 +66,12 @@ exports.save = async function(ctx) {
     },
   }
   await db.put(designDoc)
+  // update linked records
+  await updateLinksForModel({
+    instanceId,
+    eventType: EventType.MODEL_SAVE,
+    model: modelToSave,
+  })
 
   // syntactic sugar for event emission
   modelToSave.modelId = modelToSave._id
@@ -106,20 +98,16 @@ exports.destroy = async function(ctx) {
     records.rows.map(record => ({ _id: record.id, _deleted: true }))
   )
 
-  // Delete linked record fields in dependent models
-  for (let key of Object.keys(modelToDelete.schema)) {
-    const { type, modelId } = modelToDelete.schema[key]
-    if (type === "link") {
-      const linkedModel = await db.get(modelId)
-      delete linkedModel.schema[modelToDelete.name]
-      await db.put(linkedModel)
-    }
-  }
-
   // delete the "all" view
   const designDoc = await db.get("_design/database")
   delete designDoc.views[modelViewId]
   await db.put(designDoc)
+  // update linked records
+  await updateLinksForModel({
+    instanceId,
+    eventType: EventType.MODEL_DELETE,
+    model: modelToDelete,
+  })
 
   // syntactic sugar for event emission
   modelToDelete.modelId = modelToDelete._id

packages/server/src/api/controllers/record.js

@@ -1,6 +1,11 @@
 const CouchDB = require("../../db")
 const validateJs = require("validate.js")
 const newid = require("../../db/newid")
+const {
+  EventType,
+  updateLinksForRecord,
+  getLinkDocuments,
+} = require("../../db/linkedRecords")
 
 validateJs.extend(validateJs.validators.datetime, {
   parse: function(value) {
@@ -41,6 +46,14 @@ exports.patch = async function(ctx) {
   const response = await db.put(record)
   record._rev = response.rev
   record.type = "record"
+  await updateLinksForRecord({
+    instanceId,
+    eventType: EventType.RECORD_UPDATE,
+    record,
+    modelId: record.modelId,
+    model,
+  })
+
   ctx.eventEmitter &&
     ctx.eventEmitter.emitRecord(`record:update`, instanceId, record, model)
   ctx.body = record
@@ -89,29 +102,13 @@ exports.save = async function(ctx) {
   record.type = "record"
   const response = await db.post(record)
   record._rev = response.rev
-
-  // create links in other tables
-  for (let key in record) {
-    if (model.schema[key] && model.schema[key].type === "link") {
-      const linked = await db.allDocs({
-        include_docs: true,
-        keys: record[key],
-      })
-
-      // add this record to the linked records in attached models
-      const linkedDocs = linked.rows.map(row => {
-        const doc = row.doc
-        return {
-          ...doc,
-          [model.name]: doc[model.name]
-            ? [...doc[model.name], record._id]
-            : [record._id],
-        }
-      })
-
-      await db.bulkDocs(linkedDocs)
-    }
-  }
+  await updateLinksForRecord({
+    instanceId,
+    eventType: EventType.RECORD_SAVE,
+    record,
+    modelId: record.modelId,
+    model,
+  })
 
   ctx.eventEmitter &&
     ctx.eventEmitter.emitRecord(`record:save`, instanceId, record, model)
@@ -179,6 +176,13 @@ exports.destroy = async function(ctx) {
   }
   ctx.body = await db.remove(ctx.params.recordId, ctx.params.revId)
   ctx.status = 200
+  await updateLinksForRecord({
+    instanceId,
+    eventType: EventType.RECORD_DELETE,
+    record,
+    modelId: record.modelId,
+  })
+
   // for automations include the record that was deleted
   ctx.record = record
   ctx.eventEmitter &&
@@ -201,7 +205,7 @@ async function validate({ instanceId, modelId, record, model }) {
     model = await db.get(modelId)
   }
   const errors = {}
-  for (let fieldName in model.schema) {
+  for (let fieldName of Object.keys(model.schema)) {
     const res = validateJs.single(
       record[fieldName],
       model.schema[fieldName].constraints
@@ -210,3 +214,28 @@ async function validate({ instanceId, modelId, record, model }) {
   }
   return { valid: Object.keys(errors).length === 0, errors }
 }
+
+exports.fetchLinkedRecords = async function(ctx) {
+  const instanceId = ctx.user.instanceId
+  const modelId = ctx.params.modelId
+  const fieldName = ctx.params.fieldName
+  const recordId = ctx.params.recordId
+  if (instanceId == null || modelId == null || recordId == null) {
+    ctx.status = 400
+    ctx.body = {
+      status: 400,
+      error:
+        "Cannot handle request, URI params have not been successfully prepared.",
+    }
+    return
+  }
+  let records = await getLinkDocuments({
+    instanceId,
+    modelId,
+    fieldName,
+    recordId,
+    includeDoc: true,
+  })
+  ctx.status = 200
+  ctx.body = { records: records }
+}

packages/server/src/api/routes/tests/model.spec.js

@@ -45,7 +45,7 @@ describe("/models", () => {
         .expect(200)
         .end(async (err, res) => {
             expect(res.res.statusMessage).toEqual("Model TestModel saved successfully.");            
-            expect(res.body.name).toEqual("TestModel");            
+            expect(res.body.name).toEqual("TestModel");
             done();
         });
       })
@@ -201,10 +201,10 @@ describe("/models", () => {
         .expect('Content-Type', /json/)
         .expect(200)
         .end(async (_, res) => {
-            expect(res.res.statusMessage).toEqual(`Model ${testModel._id} deleted.`);            
-            const dependentModel = await getDocument(instance._id, linkedModel._id)
-            expect(dependentModel.schema.TestModel).not.toBeDefined();
-            done();
+          expect(res.res.statusMessage).toEqual(`Model ${testModel._id} deleted.`);
+          const dependentModel = await getDocument(instance._id, linkedModel._id)
+          expect(dependentModel.schema.TestModel).not.toBeDefined();
+          done();
         });
       })
 

packages/server/src/db/linkedRecords/LinkController.js

@@ -21,6 +21,10 @@ function LinkDocument(
   fieldName2,
   recordId2
 ) {
+  // build the ID out of unique references to this link document
+  this._id = `${modelId1}/${modelId2}/${fieldName1}/${fieldName2}/${recordId1}/${recordId2}`
+  // required for referencing in view
+  this.type = "link"
   this.doc1 = {
     modelId: modelId1,
     fieldName: fieldName1,
@@ -34,18 +38,12 @@ function LinkDocument(
 }
 
 class LinkController {
-  /**
-   * Create a new link controller which can be used to handle link updates for an event.
-   * @param {string} instanceId The instance in which updates will be carried out.
-   * @param {{modelId: string, model: object|undefined, record: object|undefined}} eventData data about
-   * what has occurred to drive this update - events are emitted when an operation that matters occurs.
-   */
-  constructor(instanceId, eventData) {
+  constructor({ instanceId, modelId, record, model }) {
     this._instanceId = instanceId
     this._db = new CouchDB(instanceId)
-    this._modelId = eventData.modelId
-    this._record = eventData.record
-    this._model = eventData.model
+    this._modelId = modelId
+    this._record = record
+    this._model = model
   }
 
   /**
@@ -106,9 +104,8 @@ class LinkController {
       const field = model.schema[fieldName]
       if (field.type === "link") {
         // get link docs to compare against
-        let currentLinkIds = await this.getLinkDocs(fieldName, record._id).map(
-          doc => doc._id
-        )
+        let linkDocs = await this.getLinkDocs(fieldName, record._id)
+        let currentLinkIds = linkDocs.map(doc => doc._id)
         let toLinkIds = record[fieldName]
         for (let linkId of toLinkIds) {
           if (currentLinkIds.indexOf(linkId) === -1) {
@@ -144,7 +141,11 @@ class LinkController {
   async recordDeleted() {
     const record = this._record
     // get link docs to compare against
-    let toDelete = await this.getLinkDocs(null, record._id).map(doc => {
+    let linkDocs = await this.getLinkDocs(null, record._id)
+    if (linkDocs.length === 0) {
+      return null
+    }
+    let toDelete = linkDocs.map(doc => {
       return {
         ...doc,
         _deleted: true,
@@ -196,8 +197,13 @@ class LinkController {
         await this._db.put(linkedModel)
       }
     }
+    // get link docs to compare against
+    let linkDocs = await this.getLinkDocs()
+    if (linkDocs.length === 0) {
+      return null
+    }
     // get link docs for this model and configure for deletion
-    let toDelete = await this.getLinkDocs().map(doc => {
+    let toDelete = linkDocs.map(doc => {
       return {
         ...doc,
         _deleted: true,

packages/server/src/db/linkedRecords/index.js

@@ -1,5 +1,3 @@
-const emitter = require("../../events")
-const InMemoryQueue = require("../../utilities/queue/inMemoryQueue")
 const LinkController = require("./LinkController")
 const CouchDB = require("../index")
 
@@ -16,55 +14,85 @@ const EventType = {
   MODEL_DELETE: "model:delete",
 }
 
-const linkedRecordQueue = new InMemoryQueue("linkedRecordQueue")
+module.exports.EventType = EventType
 
-function createEmitterCallback(eventName) {
-  emitter.on(eventName, function(event) {
-    if (!event || !event.record || !event.record.modelId) {
-      return
-    }
-    linkedRecordQueue.add({
-      type: eventName,
-      event,
-    })
-  })
-}
-
-for (let typeKey of Object.keys(EventType)) {
-  createEmitterCallback(EventType[typeKey])
-}
-
-linkedRecordQueue.process(async job => {
-  let data = job.data
+/**
+ * Update link documents for a model - this is to be called by the model controller when a model is being changed.
+ * @param {EventType} eventType states what type of model change is occurring, means this can be expanded upon in the
+ * future quite easily (all updates go through one function).
+ * @param {string} instanceId The ID of the instance in which the model change is occurring.
+ * @param {object} model The model which is changing, whether it is being deleted, created or updated.
+ * @returns {Promise<null>} When the update is complete this will respond successfully.
+ */
+module.exports.updateLinksForModel = async ({
+  eventType,
+  instanceId,
+  model,
+}) => {
   // can't operate without these properties
-  if (data.instanceId == null || data.modelId == null) {
-    return
+  if (instanceId == null || model == null) {
+    return null
   }
-  // link controller exists to help manage state, the operation
-  // of updating links is a particularly stateful task
-  let linkController = new LinkController(data.instanceId, data)
-  // model doesn't have links, can stop here
+  let linkController = new LinkController({
+    instanceId,
+    modelId: model._id,
+    model,
+  })
   if (!(await linkController.doesModelHaveLinkedFields())) {
-    return
+    return null
   }
-  // carry out the logic at a top level so that we can handle
-  // multiple operations for a single queue entry if desired
-  switch (data.type) {
-    case EventType.RECORD_SAVE:
-    case EventType.RECORD_UPDATE:
-      await linkController.recordSaved()
-      break
-    case EventType.RECORD_DELETE:
-      await linkController.recordDeleted()
-      break
+  switch (eventType) {
     case EventType.MODEL_SAVE:
       await linkController.modelSaved()
       break
     case EventType.MODEL_DELETE:
       await linkController.modelDeleted()
       break
+    default:
+      throw "Type of event is not known, linked record handler requires update."
+  }
+}
+
+/**
+ * Update link documents for a record - this is to be called by the record controller when a record is being changed.
+ * @param {EventType} eventType states what type of record change is occurring, means this can be expanded upon in the
+ * future quite easily (all updates go through one function).
+ * @param {string} instanceId The ID of the instance in which the record update is occurring.
+ * @param {object} record The record which is changing, e.g. created, updated or deleted.
+ * @param {string} modelId The ID of the of the model which is being updated.
+ * @param {object|null} model If the model has already been retrieved this can be used to reduce database gets.
+ * @returns {Promise<null>} When the update is complete this will respond successfully.
+ */
+module.exports.updateLinksForRecord = async ({
+  eventType,
+  instanceId,
+  record,
+  modelId,
+  model,
+}) => {
+  // can't operate without these properties
+  if (instanceId == null || modelId == null) {
+    return null
   }
-})
+  let linkController = new LinkController({
+    instanceId,
+    modelId,
+    model,
+    record,
+  })
+  if (!(await linkController.doesModelHaveLinkedFields())) {
+    return null
+  }
+  switch (eventType) {
+    case EventType.RECORD_SAVE:
+    case EventType.RECORD_UPDATE:
+      return await linkController.recordSaved()
+    case EventType.RECORD_DELETE:
+      return await linkController.recordDeleted()
+    default:
+      throw "Type of event is not known, linked record handler requires update."
+  }
+}
 
 /**
  * Gets the linking documents, not the linked documents themselves.
@@ -104,6 +132,10 @@ module.exports.getLinkDocuments = async ({
     params = { startKey: [modelId, 1], endKey: [modelId, 1, {}] }
   }
   params.include_docs = !!includeDoc
-  const response = await db.query("database/by_link", params)
-  return response.rows.map(row => row.doc)
+  try {
+    const response = await db.query("database/by_link", params)
+    return response.rows.map(row => row.doc)
+  } catch (err) {
+    console.error(err)
+  }
 }